Mutineer-Exeter Development Drilling & Completions Challenges Darren Greer & Peter Dodd

Transcription

1 Mutineer-Exeter Development Drilling & Completions Challenges Darren Greer & Peter Dodd (10 March 2005) 1

2 Outline 1. Project Overview 2. Wells Overview 3. Drilling Challenges Outcomes 4. Completions Challenges Outcomes 5. Campaign Outcomes 2

3 Project Overview North West Shelf WA 2 Fields ~160m water depth Light, sweet crude Very low GOR Subsea Development Fast-track project Santos first offshore development World first dual-esp subsea wells tied back to an FPSO 3

4 Wells Overview 30 /20 casing 13-3/8 casing 10-3/4 casing Key Features Tubing Hanger Horizontal Tree Batch drilled and completed Pilot holes utilised 2 x ESP Cables Geosteered horizontal sections ESP Packer Horizontal subsea trees 2 x ESP Dual Electric Submersible Pumps ESP Bypass Retrievable Packer Isolation Nipple Profile 5-1/2 tubing 5-1/2 sand screens 9-5/8 casing 4

5 Drilling Challenges 1. Resources (the right team) 2. Mitigating batch drilling risks 3. Top reservoir uncertainty 4. Geosteering/Palaeosteering 5

6 Drilling Challenges Resources (Team) - Santos first offshore development - Complex wells - Abundant in-house drilling expertise - Limited offshore development expertise Solution - Core staff team - Familiar with Santos systems and culture - Experience/learning retained - Team supplemented with contract personnel - Skill gaps filled 6

7 Drilling Challenges Batch Drilling Pros and Cons Pro Con - Increased operational/logistics efficiency - Reduced cost - Reduced environmental exposure - Potential increased exposure to critical design flaws - Geological unknowns - Formation damage/impaired production Solution - First well drilled and tested to prove design early in campaign - Timely incorporation of optimisations 7

8 Drilling Challenges Top Reservoir Uncertainty - Risk of sub-optimal well placement ( production) - Risk of numerous sidetracks ( cost) Solution Pilot hole - Pilot hole used to locate and evaluate reservoir - Well sidetracked once only - Production hole optimally placed Pilot hole 8

9 Drilling Challenges Geosteering - Empowered Reservoir Navigator imbedded early in subsurface team - Log response modelling performed - Straightforward decision making process Palaeosteering Approaching Shale - Contingency capability at rig - Allows rapid shale identification if a fault is intersected 9

10 Other Success Successful formation damage mitigation Early wellbore stability/geomechanics work Design eliminated 20 casing string Use of TesTrak (LWD formation pressure tool) 10

11 Outcomes 394 days continuous operations 4 Development wells drilled and completed 7 appraisal holes drilled 2 near field exploration wells drilled Wells benchmark favourably with similar development wells Demonstrated continuous improvement Measured Depth (m) Drilling Improvement ,000. 1,500. 2,000. 2,500. 3,000. 3,500. 4,000. Drilling Time Performance (Like Development Wells) 4 wells successfully geosteered Successful batch drilling Visible performance improvement across campaign Mutineer 4 (Actual) Exeter-4 (Actual) Days Completions Improvement % Downtime Completions Down-Time (Dual ESPs - Subsea Wells) Mutineer-Exeter Completions Other Operator (North Sea 2003) Days Mutineer-Exeter Completions Corrected Durations* Run XT Run BOP Run Upper Compl. Landing String Clean Up Suspend Mutineer 4 Mutineer 5 Exeter 4AH Mutineer 9H AFE 11

12 The History of Subsea ESP...Part 1 Operator A - 1 well 3 x Misruns ESP aborted, gas lift installed... 12

13 The History of Subsea ESP...Part 2 Operator B 3 wells 2 x Misruns 43% NPT 13

14 Completions The Challenge. Santos first offshore completions Fast tracked project Schedule critical Complex dual ESP subsea completions Only done successfully once before in the world 14

15 Completion Design Debris Cap Crown Plugs Tubing Hanger Horizontal Production Tree TRSCSSV 2 x ESP Cables ESP Packer Upper Completion 2 x ESP s Bypass Tubing Retrievable Nipple Profile for Deep Set Plug Retrievable Packer Tubing (5-1/2 ) upper and lower Sand Screens Lower Completion 15

16 Completions Outline Lower Completion RIH sand screens and packer. RIH latch seal assembly with deep set plug. Cleanout well to inhibited seawater. Set suspension packer. Upper Completion Install horizontal tree. Retrieve suspension packer. RIH dual ESP completion. Land tubing hanger with subsea test tree. Displace tubing to diesel, set packer. Clean up well to flare. RIH tubing hanger crown plugs. Install debris cap. Perform final electrical checks. ESPs not commissioned on rig. To be done on FPSO. 16

17 Completions Timeline FEED Study completed May 2003 Completions HAZID March 2004 Tree Profile Interface Simulation Modelling March 2004 Tubing Hanger Simulation Test April 2004 Exeter 4AH Well Test May 2004 ESP Running SIT May 2004 Subsea Tree SIT (Landing String and ROV) June 2004 Detailed design finalised June 2004 Tree Handling HAZID July 2004 Complete the Well on Paper Exercise August 2004 Completions (x4 wells) October December

18 Exeter 4AH Well Test 1 st well test of Exeter field. Well did not self kill! Enabled fine tuning of lower completion design, cleanout procedures and well test spread. 18

19 System Integration Testing Cable and equipment damage a high risk 1 week SIT $ < 1 rig day $ ESP and tubing deployment SIT at test rig in Aberdeen Tubing Hanger Simulation Test at Vetco Gray Singapore Subsea Tree SIT with Landing String and ROV at Vetco Gray Singapore 19

20 Riser Angle 2D Simulation determined system limits 1 deg contact (Damage) occurs Aberdeen SIT confirmed these limits- (skidded rig to simulate) m water depth, max 2.7m drift off station Calibration of Bullseyes Calibration of Nautronix riser monitoring system Effect of wind and tides closely monitored Regular ROV monitoring In practice <0.5deg maintained 20

21 Cable Handling Electrical Checks Retractable BJ350 Spider Lasalle Clamp Installation 21

22 Cable Handling MLE Space-out Splicing Retractable BJ350 Spider 22

23 Cable Damage During TH make up, first completion: Lost Electrical signal on Upper Pump Cable TDR indicated a fault at the XT POOH, respliced, continued RIH Incorrect space-out of Protection pups Protection effective during re-run 23

24 Subsea Alignment Aligned Tree, Rig and TH to minimise rotation when landing out Tubing Hanger Position of Cable sheaves important Influenced rig heading and manifold orientation RIG FLOOR AFT CABLE SPOOLERS PORT NORTH KEYWAY FORWARD RIG ORIENTATION: 235deg NORTH PRODUCTION FLANGE KEYWAY APPROX 30deg TUBING HANGER HORIZONTAL TREE ORIENTATION STARBOARD 24

25 BOP Modifications TH Bore offset 1-3/4 to accommodate 2 x Tronic connectors, Dogleg adaptor required between THRT (URT) & SSTT BOP Spaceout required 38 spoolpiece between LPR s and H4 connector Increased height of BOP s prevented lifting onto test stump Solution: Hydraulically Retractable H4 test stump 25

26 ESP Spool Tree Running 1 st subsea tree 26

27 ESP Spool Tree Debris Cap Spool Tree Tubing Hanger 27

28 Deck Management Formal Deck Management Plan Pre-prepared pipe onshore Additional decks installed Minimal test package Backloaded drilling gear (batched sequence) 28

29 Well Cleanliness High focus on wellbore cleanouts. Progressive improvement in well bore cleanliness Successfully retrieved all Lower Completion Junk Catchers and Plugs Sometimes very full 3ft Junk Catcher used 29

30 Phase 1 Completions Performance Days Mutineer-Exeter Completions Corrected Durations Mutineer 4 Mutineer 5 Exeter 4AH Mutineer 9H AFE Run XT Run BOP Run Upper Compl. Landing String Clean Up Suspend Time reduced from 14.5 to 10.2 days. 30% improvement 14.3% NPT 8.3% completion related NPT cf. Operator B NPT 43% TRCFR = 0 during completions. 30

31 Keys to Success SITs invaluable. - Modifying procedures and relationship building. - Saved countless hours of rig time. Planning, planning, planning! - Huge focus on attention to detail. Great team effort from all personnel involved. Continuity of personnel through planning and implementation. - Sought and secured the right people early. Rapidly applied learnings to improve efficiency. - Minimal focus on time targets yet improved by 30%! Batch setting of completions. - Significantly simplified logistics and equipment movements. 31

32 Campaign Outcomes Key Achievements - TRCRF <2 (target 10) - No lost time incidents - 44,465m of hole drilled - Longest step-out well drilled by Santos - Doubled the number of dual-esp completions worldwide - No impact on project schedule - Under budget - On time 32

33 Questions? 33